1. Field of the Invention
This invention relates to a device for feeding single sheets or the like to a packaging, labelling or packeting machine.
2. Discussion of the Related Art
Devices for feeding single sheets or the like, known as sheet feeders, and particularly when arranged at the side of an automatic machine for packaging products in material in the form of a continuous web, such as heat-shrinkable plastics film, enable supplementary sheets, or sheets which themselves form the total packaged product, to be positioned on an associated conveyor. These devices can also be associated in the same manner with labelling or packeting machines.
These devices are specifically constructed in such dimensions as to be able to handle stacks of sheets or the like of fairly predetermined dimensions. Hence a packaging, labelling or packeting machine which is required to handle products of different dimensions must comprise several associated devices of different dimensions which are operated as required, or alternatively specific devices must be able to be mounted on the machine. This obviously results in considerable plant costs in providing the entire necessary range of devices.
A further problem of feed devices of known type is that their operating rate is limited because of the intrinsic limits of the individual devices. To overcome this it is only possible at the moment to arrange several devices one behind the other and drive the conveyor with a pitch which is double the usual pitch, so that the supplementary sheets are loaded or arranged in positions corresponding with the required pusher elements. This greatly limits the production capacity of the packaging machine or results in a considerable increase in the plant and operating costs because of the number of devices.
A further problem connected with the known systems is that of synchronizing the various devices with each other and with the conveyor forming part of the packaging, labelling or packeting machine.